Re: [PATCH 42/42] hw/i386/acpi-build: Resolve PIIX ISA bridge rather than ACPI controller

[Bernhard Beschow]

Am 1. September 2022 21:05:03 UTC schrieb "Philippe Mathieu-Daudé" 
<f4bug@amsat.org>:
>On 1/9/22 18:26, Bernhard Beschow wrote:
>> Resolving the PIIX ISA bridge rather than the PIIX ACPI controller mirrors
>> the ICH9 code one line below.
>> 
>> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
>> ---
>>   hw/i386/acpi-build.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
>> index 8af75b1e22..d7bb1ccb26 100644
>> --- a/hw/i386/acpi-build.c
>> +++ b/hw/i386/acpi-build.c
>> @@ -288,7 +288,7 @@ static void acpi_get_pm_info(MachineState *machine, 
>> AcpiPmInfo *pm)
>>     static void acpi_get_misc_info(AcpiMiscInfo *info)
>>   {
>> -    Object *piix = object_resolve_type_unambiguous(TYPE_PIIX4_PM);
>> +    Object *piix = object_resolve_type_unambiguous(TYPE_PIIX_PCI_DEVICE);
>>       Object *lpc = object_resolve_type_unambiguous(TYPE_ICH9_LPC_DEVICE);
>>       assert(!!piix != !!lpc);
>>   
>
>This looks correct to  me w.r.t the hardware, but my understanding is
>some x86 machines allow abusing the PIIX ACPI PCI function, by plugging
>it alone, without the rest of the south bridge... Then this patch would
>regress such Frankenstein use :/

TYPE_PIIX4_PM is not user-creatable and is only instantiated in pc_piix.c if 
the southbridge is as well, so those should be equivalent. Since 
acpi_get_misc_info() is more about the board and south bridge and not about PM, 
I think checking for TYPE_PIIX_PCI_DEVICE is therefore more appropriate here.

>
>Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>